1. Field of the Invention
The present invention relates to a projection apparatus and a location method for the projection apparatus. More particularly, the present invention relates to a projection apparatus for determining a position of a light point on a projection image and a location method thereof.
2. Descriptions of the Related Art
In recent years, owing to gradual improvement of imaging quality, decrease in production cost and miniaturization in volume of projection apparatuses, use of the projection apparatuses no matter in enterprises, by individuals or at homes has experienced a steady increase. For example, when using a computer to make a presentation in enterprises or in academic circles, a user usually connects the computer to a projection apparatus to project an image on a projection screen.
Furthermore, when making the presentation, the user usually uses a laser pointer so that, by means of a light point outputted by the laser pointer, contents of the current presentation can be indicated in the image projected by the projection apparatus. Accordingly, to improve the value in use of the projection apparatus, the conventional projection apparatus with interaction functionality utilizes a charge-coupled device (CCD) to receive the light point outputted by the laser pointer and then determine a position of the light point on the image projected by the projection apparatus to generate a determination result. Finally, the projection apparatus outputs the position of the light point outputted by the laser pointer to the computer connected with the projection apparatus. In this way, the user will be able to operate the computer via the laser pointer.
However, as a kind of two-dimensional position sensor, the CCD must be used in conjunction with an additional lens in order to receive the light point outputted by the laser pointer. Therefore, when manufacturers produce such projection apparatuses with interaction functionality, in addition to the original lens for projecting an image, an additional lens for receiving the light point outputted by the laser pointer must be further used, which considerably increases the volume of the projection apparatus. Consequently, this makes it impossible for the projection apparatus manufacturers to produce projection apparatuses with interaction functionality on basis of miniaturized projection apparatuses of a rear projection type or a front projection type.
Accordingly, an urgent need exists in the art to provide a solution that can produce a miniaturized projection apparatus with interaction functionality to overcome the limitations in design of projection apparatuses with interaction functionality caused by the CCD.